This invention relates generally to a fuel injection valve assembly for use in a reciprocating natural gas engine and more particularly to an improved fuel injection valve which allows servicing of the valve without removal of the rocker arm and improved service life for the valve.
In the operation of reciprocating engines that operate by internal combustion of gaseous fuels as natural gas, fuel injection valves are critical to smooth operation of the engine. Typically, each cylinder of such a reciprocating engine has a fuel injection valve communicating therewith, the operation of the fuel injection valve necessary for smooth, efficient operation of the engine.
These fuel injection valve assemblies require periodic repair and maintenance due to such problems as deterioration of valve stem packing. This type of injection valve often is not enclosed within a protective rocker cover and is therefore exposed to outside airborne particles of dirt and grit. Sometimes these particles will work down the fuel injection valve's exposed surfaces into the sealing surfaces and will either damage the seal or score the outside surface of the stem piston, creating a leak passage. These repairs are costly and time-consuming and require the removal of the entire valve assembly, including rocker arm, from the engine. This removal of the rocker arm and complete valve assembly increases the amount of engine downtime and requires the technician doing the repair to handle large, heavy components such as the rocker arms. The improved fuel injection valve of the present invention overcomes the deficiencies of the prior art and provides a fuel injection valve which prevents premature damage to seal and wear surfaces and allows repair of the fuel injection valve to be effected without requiring removal of the rocker arms or the entire fuel injection valve assembly.
An example of a prior fuel injection valve is the T. Z. Fisher U.S. Pat. No. 4,365,756 which shows a fuel injection valve with exposed spring and seal surfaces exposed to airborne dirt and grit.